Invisible light television system



Jan. 11, 1949. w. A. R. MALM INVISIBLE LIGHT TELEVISION SYSTEM OriginalFiled April 15, 1944 IN V EN TOR.

Patented Jan. 11 1949 UNITED RAIRE NT OFF-ICE lzss isss- "i INVISIBBELIGHT TELEVISIONSYSTEM william A lh Malm, New Orleans, La.

27,4945, SerialNo. 625,035

, 2 Claims.

7 This application is a division of =myipending; application, Serial .Nm53l, 2 05, filed;Apri1 15,-;1944:

This-invention rrelatestg imethods and means for 1 controllinginvisible; and wisi-ble; scanning beams einan inframedeor ultrla-violetray television system and the like wherein; objectse-are scannedbycmeans of infra-red or,nlt ra+violet raysyandlaivisiblelrimage ofsaidiobject lis i rmed upon =azrscreen, and methods; and. means formechanically interlocking: the; scanning; devices in an apparatus-whichis; effectively a. television transmitter and-receivencloselycoupledthereby eliminating the enecessi-ty, of; costlyscannersynchronizing :devices.

Obj ect scanning at the transmitter-V and image scanning-at the receiver.;have both :been. accomplished. by electronic; and mechanical means;The electronic devices weresefficientbut expen e sive; while the:mechanical clevices proposed heretofore 1 were inexpensive but.inefficientcand some wereimpractical. I s

It is 1 a well .;known. factethatl' an lobject which emits or reflectsvisible light rays islinvisible to thezeye if a-foggori-hazeexists-between .the object and. the; observer, because the visiblerays-= are diffused by the-foge-or haze-,whil thegpenetrating infra-credrays areznotrdetectedqby theieye Like-:- wise,; objects which emit o1:refiectconl-y'ginirau-red or ultra-violet rays are @not visi bleeto.theceye.

This invention provides, means for scannmg :a television obj cat; which,-emits,or reflects; visible light raysbutis obscured r-by fog or haze,or. a television object emitting or: reflectingeinfra-lredorultra-violet-rays an'd,.enveloped in darkness, andlmeanstfor scanninga television image. offsaid object upon aisuitable screen; comprisedoffinfrared or ultra-violetnray.detecting devices, transducersfor.convertingtheinfra-red ,or-ultra-violet scanningerays intovisibleilight scanning rays, invisible and visible raykineto-opticalLdevices, etc., hereinafter described. 7 .An object ofthis inventionis to provide practicalimeansfor viewing an objectenvelopednin darkness, fogcor haze.

Other objects of this invention, will appear hereinafter.

. The views inthe drawing are entirelylsectional, to.facilitateillustration of theeopticalldevices.

The, drawing .shows .the invention asvapplicable to infra-red orultra-violetv television, ,,wherein visible, television images of vobjects which emit or. reflect, invisible, but retractable. rays are.received .upon' a suitable viewingscreen. Thedee vices. effectivelycomprise, a, transmittencobject as Lorre 10f: the kineto=opticalrprismaticr lenses functionssimultaneouslyas antobject and imagescanners.therebyueliminating the. necessity of otherxzsynchroniingimeans. The drawing" is a vertical plane section embodying relateddevices fcrzpr-odncingv:televisionsimageaof objects,- the directovisionof: which liS' obstructed iby darkness; fog :or-whazen Theoparallelscanning- .lrreazmsx of light rays and infra-red or ultra-violetrayslare shown proportionately over-sized, aas'; illa isaquite enviousthatihight quality picturedetail can be ohtainedionly' whensaidapazrallel scanning beams arecextremiellyyzsmall ingtheircrossesectionalrarea .;l3,escrinticn;cfthe:devicesxshownainithedrawillisclose theirroperation.. v -Flhe erefractive devicesnshownl in: thedrawing could be useful.@ifnconstmcted; of 1 conventional optiealimediaw crown andxfiint glass ihOWBVBI', for reflection of infraered;;or=;ultra-violet; rays the: efiiciency; of; said refractive-,.devijces {would be increasedaif th y; wer made .of, pol tyrene: orsimilar :plastic "material.

31 represents ,1 an: object beingscanned :-;by a beam niiinfna red ;orultra-violet vrays .3-2. :33-.is a suitalblezfilter which ;.al1o.wseither. infra-red or ultra-v o eta vsit ppass, as I y; abereq Theubeam,ofgira-ys lslrcon-ldrb'e emitted from an object ,:radiating-:,inf1za+red. --or ultra'rvioletrays, 0r:"1t fl@C;l d'-: r0m :en 1 objectflooded h infrared or ultra-violet rays. Theaefiective=focus..of lensassembly ,3sl andz 35 :(preierablwmade of polystyrene or similar plasticmateria-l).-:determincs thewsize pf :thfirfijeldfof View being scanned.V v 1 gylinglrical; lens- 3 6 :omzerges,v in a vertical pl n mal o i hrays:intercep edwhyl n s e ly ,34 1111165., 7 s

Br matic, lensfil is a polyhedron (with al cone ce I ri'c'. circularhole; which rotates :in 'a'lvert-ica'l wplan eeatpa ccnstantl speeds Itsspeed ;must be consistent with the numbei ;of. .;polyg-onal sidesentitle-polyhedron,image scanning line-,and-gframe frequencies;theflpractica-l limits of rotational c s-1 s a n I Cylindricali lens138. converges; ninja [horizontal plane; a ,ofthe-rayssvertically-deflected by;rotat:- ing pris matic lens, 31'. v

ismatil lens- 911s a polyhedr nW -me centric. circular hole; whichrotates in .-a horizontaL-plane-and atiaficcnstantispeed, I-Its speedmust be consistent-with the numbernof. polygonal theepolyhedron, imagescanningslinet and name ,freqnencies; and;-the practical limits ofscanner and, receiver image: scaxmerev directly rotationaLdevices Thespeed of rotation of prismatic lenses 3! and 39 increases with therequired number of image scanning lines and frames per second, andvaries inversely as the number of polygonal sides.

The means for rotating and synchronizing prismatic lenses 31, 39, and 46are not shown in the drawing, for simplicity, as they are conventionaldevices.

The aperture in plate 40, by virtue of the related positions ofprismatic lenses 3! and 39, allows only the infra-red or ultra-violetrays from the spot of the object which is being scanned at each instantto enter the photo-electric cell symbolized by 4|.

Photo-electric cell 4| converts the infra-red or ultra-violet rayimpulses passing through aperture in plate 40 into electrical impulseswhich are passed through amplifier symbolized by 42. Amplifier 42 givesthe said electrical impulses sufficient gain to operate the neon, argon,or similar gas crater type of lamp symbolized by 43. This inventioninvolves the use of any suitable transducer which would convert theelectrical impulses into light impulses within a parallel beam of lighthaving an extremely small cross sectional area.

The parallel beam of light 44 emitted from said neon lamp 43, obviouslywould carry the modulations of the invisible infra-red or ultra-violetray beam 32.

Prismatic lens 46 is a polyhedron with a concentric circular hole, whichrotates in a horizontal plane (1. e., relative to the rotational planeof prismatic lens 31) and at a constant speed. Its speed must beconsistent with the number of polygonal sides of the polyhedron, imagescanning line and frame frequencies, and the practical limits ofrotational devices.

The concentric circular hole in prismatic lenses 37, 39 and 46 providesmeans for increasing the total deflection of the beams refracted by saidprismatic lenses, to compensate for reduced refraction in the polyhedroncaused by increasing the number of polygonal sides in order to obtain arotational speed within practical limits and commensurate with presentday standards of line and frame frequencies. Experiments havedemonstated that the angle of total deflection of the scanning beamwithin the polyhedron varies inversely as the diameter of the concentriccircular hole.

As light beam 44 passes through rotating prismatic lens 31, it isvertically deflected and scans a vertical line upon screen 50 each timea polygonal side sweeps through said light beam.

Light beam 44 follows a succession of divergent paths in a verticalplane. as it is deflected by rotating prismatic lens 31. Thesesuccessively divergent paths are paralleled by means of cylindrical lens45, so that said light beam 44 may be properly deflected by prismaticlens 46 rotating in a horizontal plane.

Light beam 44 then passes through rotating prismatic lens 46, itshorizontal deflection causing the vertical lines scanned upon screen 50by prismatic lens 31 to appear adjacent to each other in rapidsuccession, as each polygonal side of prismatic lens 46 sweeps throughsaid light beam.

Light beam 44 follows a succession of divergent paths in successivehorizontal planes, as said light beam is vertically deflected byprismatic lens 31 and simultaneously deflected horizontally by prismaticlens 46. These successively divergent paths, in successive horizontalplanes, are paralleled by means of cylindrical lens 41 thusly form-- 4ing a television image with the modulations of light beam 44 forprojection upon screen 50.

The size of the television image appearing upon screen 50 is determinedby the effective focus of lens assembly 48 and 49.

Observer 5| can make the devices sensitive to infra-red, ultra-violet,or visible rays by simply changing or removing the filter 33, as may berequired.

The infra-red or ultra-violet sensitivity of photo-electric cell 4!would be increased, if at least a portion of the bulb through which therays pass was made of polystyrene or similar plastic material.

This invention may have other embodiments without departing from itsspirit.

Whatis claimed as new and desired to be secured by Letters Patent is asfollows:

1. In the art of television and the like, a device which combines thescanning of an object with the scanning of an image of said object forthe purpose of viewing said object when enveloped in fog, haze, ordarkness, comprising a lens assembly for intercepting a succession ofparallel beams of infra-red or ultra-violet rays radiated from thesurface of said object, means for filtering said successive parallelbeams, a dual purpose rotating polyhedronal prismatic lens having aconcentric circular hole and related cylindrical lenses providing meansfor simultaneously and vertically deflecting said successive parallelbeams of infra-red or ultra-violet rays and a parallel beam of visiblelight rays hereinafter described, a second rotating polyhedronalprismatic lens having a concentric circular hole and related cylindricallens for horizontally deflecting said parallel beam of infra-red orultra-violet rays, and an aperture plate which by virtue of thesuccessive related positions of the said rotating prismatic lensesallows only the rays within said infra-red or ultra-violet scanning beamto convey modulating impulses to a photo-electric cell; a photo-electriccell or similar device, an amplifier and related means for producing aparallel image scanning visible light beam modulated by the outputimpulses of said amplifier, a third rotating polyhedronal prismatic lenshaving a concentric circular hole and related cylindrical lens fordeflecting said parallel beam of'modulated visible light rays in a planeperpendicular to the plane in which said modulated beam of visible lightrays are deflected by the aforementioned dual purpose rotatingpolyhedronal prismatic lens, and a lens assembly providing means fordetermining the total viewing screen area scanned by said modulatedparallel visible light beam thereby determining the size of thetelevision image projected upon said screen.

2. In the art of television and the like, means for producing andcontrolling object and image scanning beams, comprising a lens assemblyfor intercepting a succession of parallel visible or invisible objectscanning beams emitted or reflected from the surface of said object,means for filtering said successive parallel beams, a kineticopticalpolyhedronal prismatic lens having a con-- centric hole or core ofrequired refractive index and related cylindrical lenses providing meansfor simultaneously and vertically defiectingsaid successive parallelvisible or invisible beams and a parallel image scanning visible lightbe m hereinafter described, and a second kineto-optical polyhedronalprismatic lens having a concentric hole or core of requiredrefractiveindex and a related cylindrical lens providing means forhoriproducing said parallel image scanning visible light beam having anextremely small cross-sectional area and extending to the viewingscreen, a third kineto-optical polyhedronal prismatic lens having aconcentric hole or core of required refractive index and a relatedcylindrical lens providing means for deflecting said parallel beam ofmodulated visible light rays in a plane perpendicular to the plane inwhich said beam of visible light rays are deflected by theaforementioned dual purpose kineto-optical polyhedronal prismatic lens,and a lens assembly for controlling the projection of said modulated anddeflected parallel image scanning visible light beam upon said viewingscreen to produce an enlarged scanned image of the scanned said object.

WILLIAM A. R. MALM.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,781,799 Baird Nov. 18, 19302,213,307 Elliott Sept. 3, 1940 2,222,987 Dimmick Nov. 26, 19402,225,097 Cawley Dec. 17, 1940 2,262,942 Jones Nov, 18, 1941

